The paper examines morphological-biological characteristics of beech fruit and seed growing at different altitudes. Research was conducted in seven localities in the area of Velebit at altitudes ranging from 521 to 1,535 m a.s.l. Fruits were collected and yield rates were assessed during autumn 2007. Seed analyses were performed in the seed and nursery production laboratory of the Department of Forest Ecology and Silviculture of the Faculty of Forestry of Zagreb University. All the elements of seed quality were tested in accordance with the ISTA rules (International Rules for Seed Testing, 2006). The average beech nut viability obtained with the tetrazolium method was 81.4%. A positive and significant (r= 0.69452) correlation between the altitude and empty (non-vital) beech seed was confirmed. The average weight of 1,000 seeds was 118.9 g. A correlation between altitude and weight of 1,000 seeds was negative and significant (r= -0.6315). The average beechnut weight from all the seven localities was 0.24 g. There were statistically significant differences in beechnut weight in relation to the localities under study. A statistically significant difference in beechnut length was established with regard to yield rate described as average and very good, or good and very good. The average beechnut length at average yield amounted to 14.72 mm, at good yield it was 15.05 mm, and at very good yield it was 16.03 mm. The overall laboratory beech seed germination after 17 weeks of testing in sand at a constant temperature of 5 C was the highest in the Krecelj locality (39.3%) and the lowest in the Velika Stražbenica locality (34.8%), whereas average germination was 37.3%. A correlation between altitude and laboratory seed germination was positive and significant (r= 0.48350). With a rise in the altitude of provenances, laboratory germination of beechnut increases significantly.